Long-term outcome for gastric marginal zone lymphoma treated with radiotherapy: a retrospective, multi-centre, International Extranodal Lymphoma Study Group study.

BACKGROUND: We evaluated the long-term results of radiotherapy for patients with gastric marginal zone lymphoma (GMZL). PATIENTS AND METHODS: We carried out a retrospective, multi-centre study of patients with low-grade GMZL treated by radiotherapy between 17 July 1981 and 25 March 2004. RESULTS: There were 102 eligible patients. Fifty-eight patients were previously untreated and 44 had recurrent/residual disease after prior treatment (HP eradication, chemotherapy and surgery in 35, 9 and 8 patients, respectively, and 7 had >1 prior therapy). Radiation fields included the stomach /involved nodes in 61 patients and whole abdomen in 41. The median radiotherapy dose to stomach was 40 Gy (range 26-46 Gy) in a median 22 fractions. With a median follow-up after radiotherapy of 7.9 years (range 0.3-24 years), 10- and 15-year freedom from treatment failure (FFTF) was 88% (95% CI 82%-95%). Risk factors for TF were a large-cell component (P = 0.036) and an exophytic growth pattern (P = 0.042). Radiotherapy field size, radiotherapy dose, and failure of prior therapy were not associated with inferior FFTF. Ten-year overall survival was 70% (95% CI 60%-82%). CONCLUSIONS: Radiotherapy achieves cure for the majority of patients with low-grade GMZL, including patients who have had prior therapy. Several features may predict a poorer outcome.

Comparison of the radiosensitivity of normal-tissue cells with normal-tissue reactions after radiotherapy.

PURPOSE: To investigate whether the in vitro radiosensitivity of normal lymphocytes and fibroblasts evaluated by the micronucleus (MN) assay predicts acute and late reactions after radio-therapy in cancer patients. MATERIALS AND METHODS: Studies were performed on blood samples from 31 cervical and head and neck cancer patients and on skin fibroblasts from eight of the cancer patients. The radiosensitivity of lymphocytes and of fibroblasts was also assessed in 24 and five healthy donors, respectively. Radiosensitivity was measured after in vitro irradiation with doses ranging from 2 to 5 Gy using micronucleus frequency (the number of micronuclei per single binucleated (BN) cell) and the percentage of BN cells with micronuclei. The in vitro results were compared with the maximum grade of acute and late reactions. RESULTS: There was no significant difference in cellular radiosensitivity between cancer patients and healthy donors. Although cancer patients differed considerably in normal-cell radiosensitivity, no correlation was found between radiosensitivity, either of lymphocytes or fibroblasts, and acute and late clinically observed side effects. In addition, no relationship was observed between the radiosensitivity of lymphocytes and fibroblasts derived from the same donors. CONCLUSION: The data do not support the usefulness of the MN assay in predicting normal-tissue response to radiotherapy in cancer patients.